Laricoideae | |
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Subalpine larch ( Larix lyallii ) in Wenatchee National Forest, Washington, U.S. | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnosperms |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Pinales |
Family: | Pinaceae |
Subfamily: | Laricoideae (Rendle) Pilg. & Melch. (1954) |
Type genus | |
Larix | |
Genera | |
The Laricoideae are a subfamily of the Pinaceae, a Pinophyta division family. They take their name from the genus Larix (larches), which contains inside most of the species of the group and is one of only two deciduous genera of the pines complex (together with Pseudolarix , which however belongs to a different subfamily, the Abietoideae). Ecologically important trees, the Laricoideae form pure or mixed forest associations often dominant in the ecosystems in which they are present, thanks also to their biological adaptations to natural disturbances, to reproductive strategies put in place and high average longevity of the individuals. Currently are assigned to this subfamily three genera ( Larix , Pseudotsuga and Cathaya ) and its members can be found only in Northern Hemisphere. [1] The various species live for the most part in temperate or cold climates and are the more northerly conifers; some constitute an important source of timber and non-timber forest products.
The species of the subfamily Laricoideae are evergreen or deciduous trees that can reach the greater heights in the Pinaceae family (over 100 meters with Pseudotsuga menziesii var. menziesii [2] ). The leaves are needle-like [1] and have primary stomatal bands only on the abaxial surface (below the phloem vessels). All members are monoecious, with separate sexes on the same plant but in different reproductive structures. The annual cones (strobili) have no distinct umbo and the scales show a broad base which, at observation, completely hides the seeds from the abaxial view. These last are whitish and firmly fixed to the wing (this thin membrane also keeps the seed well attached to the scale during maturation); furthermore, among the typical distinctive features of the group, we have the micropylar fluid of the strobilus absent, no resin vesicles on the seeds [1] and the presence, in the vascular cylinder of the young root, of two characteristic small resiniferous canals. The bark and the wood of the genera Larix and Pseudotsuga have a similar anatomy and morphology: the reddish color of the heartwood and the white-yellowish of the sapwood, the high specific weight compared to other conifers, the distribution of late and earlywood, the presence of resiniferous channels and their localization in the tissuets, the molecules that form the resin and extractives, the chemical, physical and mechanical properties as well as the class of resistance to the attack of pathogens such as fungi and insects are a clue of a common ancestral origin. Similar between the two genera are also some aspects of the phenology, the degree of shade tolerance, the fire-resistant marbled bark and the appearance of the young shoots.[ citation needed ]
The subfamily Laricoideae was described with the actual name by Robert Knud Friedrich Pilger and Hans Melchior in late 1954 [3] and subsequently modified by other authors in the course of time as regards the taxa of belonging. Before that, the genera Larix , Pseudotsuga and Cedrus were gathered in a provisional subfamily called Laricinae, defined for the first time by Melchior and Werdermann always in 1954 (...“trees that have both short and long shoots, monomorphic leaves, and strobili borne on the short shoots”...) and rechristened immediately after with the current term. The grouping in this form was confirmed by Hart (1987) through cladistic analysis, but already in 1988 Frankis replaced Cedrus with Cathaya (a genus described for the first time in 1962) in a new classification (now obsolete) that saw Larix as a distinct twin group compared to Cathaya - Pseudotsuga .[ citation needed ]
Historically the Laricoideae were the subfamily of the Pinaceae comprising the trees with needles inserted both on the macroblasts and on the brachiblasts; for this reason in the past they have been also included in it the genera Pseudolarix (for a short time) and Cedrus , subsequently eliminated following the most recent systematic updates developed on the basis of molecular genetic phylogeny, reproductive morphology, chromosome numbers and immunology. Currently, based on these studies, there are three genera in the subfamily Laricoideae, of which one of which is monotypic as it consists of only one species: [1]
Image | Genus | Description | Living species |
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![]() | Larix Mill. | Larches are the genus type of this subfamily. Deciduous trees, they live in cold climates at elevate altitude in the mountains of temperate zones or at high latitudes in the Northern Hemisphere. They are found in North America, Central Europe and Northern Asia (Russia, Japan and China). |
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![]() | Pseudotsuga Carrière | Douglas-firs are medium to extremely large trees and often resemble morphologically as species of Abies or Tsuga . Have cones pendulous with persistent scales and three-pointed bract sticking out from the structure. They are found in the temperate mountains of North America and Eastern Asia, where they can reach 100 m in height ( Pseudotsuga menziesii var. menziesii ). |
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| Cathaya Chun & Kuang | Monotypic genus with only one species: Cathaya argyrophylla. The leaves are needle-like, evergreen, 2.5–5 cm long with ciliates margins when young; they grow in spiral patterns around sprig. Cones 3–5 cm long with 15-20 scales, each scale bearing two winged seeds. This conifer grows in Southern China, in provinces of Guangxi, Guizhou, Hunan and southeast Sichuan on steep mountain slopes between the 950 and 1800 m of altitude. |
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Within the subfamily the genera Larix and Pseudotsuga are more closely correlated to each other ( sister taxa ) than Cathaya . This evidence is demonstrated by numerous biological and macro-micro morphological similarities between the larches and the Douglas-firs including, but not only, a various tissues common anatomy, immunology of seed protein and the absence of the two air sacs in the pollen, typicals instead of the other Pinaceae. The similarities between the pollen grains of the genera Larix and Pseudotsuga however do not stop here [5] and include other aspects as: granules not buoyant, atectate, with external wall (exospore) granular, pollination drop containing xylose [6] and the presence of an exine shell during microgametophyte germination. Doyle and O'Leary (1935) [5] furthermore described a pollination process very similar in Larix and Pseudotsuga where the granule, which lacks air sacs, lands on an almost stigmatic extension of the integument, the margins of which tend to inroll. The contact with the nucellus may ( Larix ) or may not ( Pseudotsuga ) be needed for pollen tubes to develop, but the mechanism is almost analogous. The time from pollination to fertilization in these two genera may be over a year and the granules germination can take months (Little et al., 2014). [5]
Price et al. he supposed in 1977 that the Laricoideae were a subfamily sister of the Abietoideae rather than the Pinoideae - Piceoideae group and this version was confirmed by Hart (1987), Frankis (1988), Farjon (1990), Wang et al. (2000) and Gernandt et al. (2008), although it has not yet found application in the literature.
The dichotomous key to recognizing the genera included to the subfamily Laricoideae is relatively simple, since only three of them belong to it and one of these is deciduous. Below is reported the taxonomic identification scheme in the form of a table:
1. Laricoideae (includes Larix , Pseudotsuga and Cathaya ): 2
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According to the latest research still in progress, [7] the genus Cathaya would be attributed to the grouping of pines (subfamily Pinoideae), leaving therefore only Larix and Pseudotsuga to forming the subfamily Laricoideae. Furthermore, studying the mitochondrial rps3 gene, Ran et al. (2010) [5] found that Larix and Pseudotsuga are evolutionarily sister genera to all other Pinaceae, highlighting a different (sub-parallel) origin compared than the remaining species. Spellenberg, Earle and Nelson (2014) [8] report that the larches and Douglas firs evolved from the Pinaceae 135 million years ago and they kept a common ancestor until 7 million years ago, thus forming a divided and closely related taxonomic line between them compared to the rest of the group, while maintaining a strong degree of kinship with it. For Wang et al (2000), [9] instead, Pseudotsuga differentiated himself from Larix in Western North America about 65 million years ago, in an era between the late Cretaceous and the Paleocene. These revisions and interactions, which would find evidence in genetics, however are not universally accepted [1] and many botanics, researchers and scientists still use the previous classification waiting for further developments.
For other authors, finally, the subfamily Laricoideae would have no taxonomic dignity of its own, recognizing only two large multi-group clades (Pinoid and Abietoid [10] ) or subfamilies (Pinoideae and Abietoideae [11] ) in their cladistics systems. Larix , Pseudotsuga and Cathaya would be included in the pines complex. [11]
Pseudotsuga is a genus of evergreen coniferous trees in the family Pinaceae. Common names for species in the genus include Douglas fir, Douglas-fir, Douglas tree, Oregon pine and Bigcone spruce. Pseudotsuga menziesii is widespread in western North America and is an important source of timber. The number of species has long been debated, but two in western North America and two to four in eastern Asia are commonly acknowledged.
Cedrus, with the common English name cedar, is a genus of coniferous trees in the plant family Pinaceae. They are native to the mountains of the western Himalayas and the Mediterranean region, occurring at altitudes of 1,500–3,200 m in the Himalayas and 1,000–2,200 m in the Mediterranean.
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta, also known as Coniferophyta or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. The division Pinophyta contains seven families, 60 to 65 genera, and more than 600 living species.
The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers. The distinguishing characteristic is the reproductive structure known as a cone produced by all Pinales. All of the extant conifers, such as Araucaria, cedar, celery-pine, cypress, fir, juniper, kauri, larch, pine, redwood, spruce, and yew, are included here. Some fossil conifers, however, belong to other distinct orders within the division Pinophyta.
Larches are deciduous conifers in the genus Larix, of the family Pinaceae. Growing from 20 to 45 metres tall, they are native to the cooler regions of the northern hemisphere, where they are found in lowland forests in the high latitudes, and high in mountains further south. Larches are among the dominant plants in the boreal forests of Siberia and Canada. Although they are conifers, larches are deciduous trees that lose their needles in the autumn.
The gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae. The term gymnosperm comes from the composite word in Greek: γυμνόσπερμος, literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or on their own as in yew, Torreya, Ginkgo. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on the sporophytic phase. The term "gymnosperm" is often used in paleobotany to refer to all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used.
The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, piñons, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae are supported as monophyletic by their protein-type sieve cell plastids, pattern of proembryogeny, and lack of bioflavonoids. They are the largest extant conifer family in species diversity, with between 220 and 250 species in 11 genera, and the second-largest in geographical range, found in most of the Northern Hemisphere, with the majority of the species in temperate climates, but ranging from subarctic to tropical. The family often forms the dominant component of boreal, coastal, and montane forests. One species, Pinus merkusii, grows just south of the equator in Southeast Asia. Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California.
Tsuga is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock. Unlike the latter, Tsuga species are not poisonous.
Cathaya is a genus in the pine family, Pinaceae, with one known living species, Cathaya argyrophylla. Cathaya is a member of the subfamily Laricoideae, most closely related to Pseudotsuga and Larix. A second species, C. nanchuanensis, is now treated as a synonym, as it does not differ from C. argyrophylla in any characters.
Cedrus deodara, the deodar cedar, Himalayan cedar, or deodar, is a species of cedar native to the Himalayas.
Pseudolarix amabilis is a species of coniferous tree in the pine family Pinaceae. The species is commonly known as golden larch, but being more closely related to Keteleeria, Abies and Cedrus, is not a true larch (Larix). P. amabilis is native to eastern China, occurring in small areas in the mountains of southern Anhui, Zhejiang, Fujian, Jiangxi, Hunan, Hubei and eastern Sichuan, at altitudes of 100–1,500 m (328–4,921 ft). The earliest known occurrences are of compression fossils found in the Ypresian Allenby Formation and mummified fossils found in the Late Eocene Buchanan Lake Formation on Axel Heiberg Island.
Larix decidua, the European larch, is a species of larch native to the mountains of central Europe, in the Alps and Carpathian Mountains as well as the Pyrenees, with disjunct lowland populations in northern Poland and southern Lithuania. It is widely naturalized in Scandinavia. Its life span has been confirmed to be close to 1000 years but is more often around 200 years. It is claimed that one of the larches planted by the second Duke of Atholl at Dunkeld in 1738 is still standing.
Nothotsuga is a genus of coniferous trees in the family Pinaceae endemic to China. Nothotsuga contains only one species, Nothotsuga longibracteata, commonly known as the bristlecone hemlock, which is found in southeastern China, in southern Fujian, northern Guangdong, northeast Guangxi, northeast Guizhou, and southwest Hunan.
Keteleeria is a genus of three species of coniferous trees in the family Pinaceae first described as a genus in 1866.
Pseudolarix is a genus of coniferous trees in the pine family Pinaceae containing three species, the extant Pseudolarix amabilis and the extinct species Pseudolarix japonica and Pseudolarix wehrii. Pseudolarix species are commonly known as golden larch, but are not true larches (Larix) being more closely related to Keteleeria, Abies and Cedrus. P. amabilis is native to eastern China, occurring in small areas in the mountains of southern Anhui, Zhejiang, Fujian, Jiangxi, Hunan, Hubei and eastern Sichuan, at altitudes of 100–1,500 m (328–4,921 ft). P. wehrii is described from fossils dating to the Early Eocene (Ypresian), of Western North America where it is found in the Eocene Okanagan Highlands Allenby and Klondike Mountain Formations. The youngest known occurrence is of mummified fossils found in the Late Eocene Buchanan Lake Formation on Axel Heiberg Island. P. japonica is known from Middle Miocene to Pliocene sediments in Japan and Miocene deposits of Korea. Fossils assigned to Pseudolarix as a genus date possibly as old as the Early Cretaceous Hauterivian stage in Mongolia.
Larix kaempferi, the Japanese larch or karamatsu in Japanese, is a species of larch native to Japan, in the mountains of Chūbu and Kantō regions in central Honshū.
Abietoideae is a subfamily of the conifer family Pinaceae. The name is from the genus Abies (firs), which contains most of the species in the genus. Six genera are currently assigned to this subfamily: Abies, Cedrus, Keteleeria, Nothotsuga, Pseudolarix, and Tsuga.
Larix griffithii, the Sikkim larch, is a species of larch, native to the eastern Himalaya in eastern Nepal, Sikkim, western Bhutan and southwestern China, growing at 1,800–4,100 metres (5,900–13,500 ft) in altitude.
Gomphidius is a genus of mushrooms, commonly known as spike-caps, that are members of the Boletales, or pored fungi. They appear to have gill-like structures which resemble those of agarics, however the similarity is superficial only. The best-known member is the slimy spike-cap. The genus has a widespread distribution, especially in north temperate areas, and contains 10 species.
Abies chensiensis, the Shensi fir, is a fir native to Gansu, Hubei, Sichuan, Tibet, Yunnan in China, and Arunachal Pradesh in India. It was first described by Philippe Édouard Léon Van Tieghem in 1892.